Control device for change-speed gears



' Aug. 8, 1939'.

E. DA USCH 2,168,667

CONTROL DEVICE FOR CHANGE-SPEED GEARS Filed March 12, 1958 2 Sheets-Sheet l Zap-gnaw nsme 1939- E. DAUSCH 2,168,667

CONTROL DEVICE FOR CHANGE-SPEED GEARS Filed March 12, 1938 2 Sheets-Sheet 2 Patented Aug. 8, 1939 UNITED STATES PATENT OFFICE Erwin Dausch, Friedrichshafen-on-the-Bodensee, Germany, assignor bau Gesells'chaft mit to Maybach-Motorenbeschrankter llaftung,

- Friedrichshafen-on-the-Bodensee, Germany, a

corporation of Germany AppllcationlnMarch 12,

1938, Serial No. 195,622

Germany June 30, 1937 4 Claims.

The present invention relates to control devices for the pressure medium of gear-changing devices of gear-wheel change-speed gears, more particularly in motor vehicles, of the kind in which'the engagement of one or more of the speed ratios has to be effected in stages, a first stage taking place, for example, with acceleration of a clutch member or other positive-engaging gear ratio change member to be engaged and another with retardation of a clutch member or other positive-engaging gear ratio change member. In such control devices it has already been proposed to provide shut-oil members, dependent upon the transmission stages, by means of which the admission of pressure medium to the gear ratio changing cylinders is controlled in such a manner that during the operation of the gear ratio changing cylinder effecting one stage, the admission of pressure medium is prevented to the gear ratio changing cylinders of those transmission stages which require a different kind of gear ratio change.

. The object of the present invention is to provide an improved construction of such control devices from the point of view of simplification, reduction of leakage and improved reliability of operation.

According to the invention, the shut-oil members dependent upon the transmission stages control a main shut-cit member which is common to them and controls the admission to the control conduits of cylinders requiring a different kind of gear ratio change.

In the accompanyin drawings, Figure 1 shows 35 a gear mechanism provided with a control device'according to the invention. A constructional form of such a control device, which is arranged in front of the parts shown in Figure 1 and which in the present case is operated for example by means of vacuum is shown by way of example in Figure 2, principally in section. The change-speed gear comprises a sectional main shaft carrying the gear wheels 1, 8, 9, l0 and a sectional layshaft carrying the gear wheels ll, i2, II and H. The gear wheels 1, 9, II and i3. are fast on their corresponding shaft sections 1, 2, l-and 5 or 6, while gear wheel I0 is freely rotatable on shaft section 3 and gear wheel I is splined on shaft section 6. Gear wheels 1, 8, 9, II and I2 are mounted with their hubs IS in the housing i6, gear wheels 8 and 12 having bores in which the adjacent shaft sections l and 2 or 4 and 5 are mounted. Betwen the permanently meshed pairs of wheels ill I, 8/" and 9/" are change-speed dog clutches l1, II and I9, 20,

which in the present case, particularly for the purpose of shortening the overall length, are constructed in such a manner that the clutches l1 and I9 are in the main shaft train and the corresponding clutches. l8 and 20, respectively, are in the layshaft train. The clutch-shifting lever 2i connecting the clutches l1 and I8 together is secured to a shaft 22 and the clutch-shifting lever 23 for actuating the clutches l9 and 20 is secured to a shaft 24. In addition, on the shaft section 3, is splined a double dog clutch 25, its teeth 25' being adapted to be brought into engagement with corresponding dog teeth of the gear wheel 9, and its teeth 25 being adapted to be brought into engagement with corresponding dog teeth on v shifting lever 26 for this change-speed dog clutch 25 is fast on a shaft 21. The clutch teeth of all the clutches (l1, l8; I9 20; 25) are provided with bevelled end faces, whereby engagement of the clutches is effected in known manner at the moment of overtaking.

Mounted on a further short layshaft is a reversing drive 30, 3|, the gear wheel. 30 whereof can be brought into engagement with the gear wheel ll, when, the latter has been shifted to the left, and

' The bevelling of the end faces of the dogs indicated in Figure 1 corresponds to the direction of rotation shown at wheel 1 in Figure 1. Starting for example from the engagement of the clutch H with the clutch member provided in gear wheel 8, as indicated in Figure 1, and if instead thereof the clutch i8 is to be brought into engagement with the corresponding clutch member mounted on gear wheel l2, then when the dogs of clutch I8 are applied to the dogs con- ,nected to gear wheel l2, be running more quickly and will therefore reject the dogs of clutch l8 (position of rejection). It now, by opening the throttle, the driver increases the speed of gear wheel 1 and hence also of gear wheel II and of the clutch l8 connected to shaft 4 of said gear wheel I I, the clutch 18 will finally overtake the counter-clutch member connected to gear wheel of the clutch will be effected in known manner. Engagement takes place in a similarmanner when clutch I8 is brought out of engagement and clutch I1 is engaged. In this case, the clutch member connected togear wheel 8 is' 'the more slowly running member. The dogs of the, at first, more rapidly running clutch H, which move past the said clutch member connected to gear the gear wheel ill. The clutch its gear wheel 3! can be brought into engagement with the gear wheel I0.

the latter dogs will first I2 and the engagement...-

wheel '8 will be rejected until, due to the diminishing speed of the engine, their speed will also fall below that of the clutch member connected to gear wheel 8, engagement then taking place.

If the gear mechanism shown in Figure 1 permitting eight forward and four reverse speeds is employed as a seven speed gear, the following sequence of speeds may be obtained for example, 29 teeth beingprovided for example on the gear wheel 1, 40 teeth on gear wheel 8.. 35 on gear wheel 9, 44 on gear wheel I0, 60 on gear I I, 48 on gear wheel I2, 53 on gear wheel I3 and 22 teeth on gear wheel I4;

Forward:

I. Shaft I, gear wheel 1, gear wheel II, shaft 4, clutch I8, gear wheel I2, gear wheel 8, clutch I9, shaft 2, gear wheel 9, gear wheel I3, shaft 6. gear wheel I4, gear wheel I0, clutch 25", shaft 3.

II. Shaft I, gear wheel I, gear wheel II, shaft 4, clutch I8, gear wheel I2, clutch 20, shaft 5, gear wheel I3, shaft 6, gear wheel I4, gear wheel I0, clutch 25", shaft 3 III. Shaft I, clutch I1, gear. wheel 8, clutch I9, shaft 2, gear wheel 9, gear wheel I3, shaft 6, gear wheel I4, gear wheel I0, clutch 25";

IV. Shaft I, gear wheel 1, gear wheel II, shaft 4, clutch I8, gear wheel I2, gear wheel 8,- clutch I9, shaft 2, gear wheel 9, clutch 25, shaft 3.

V. Shaft I I, gear wheel 1, gear wheel II, shaft 4, clutch I8, gear wheel I2, clutch 20, shaft 5, gear wheel I3, gear wheel 9, clutch 25', shaft 3.

VI. Shaft I, clutch I1, gear wheel 8, clutch I9, shaft 2, gear wheel 9-, clutch 25', shaft 3 (direct drive).

VII. Shaft I, clutch I1, gear wheel 8, gear wheel I2, clutch 20, shaft 5, gear wheel I3, gear wheel 9, clutch 25', shaft 3 (speed shown in drawings).

A reverse drive is for example:

Shaft I, gear wheel 1, gear wheel II, shaft 4, clutch I8, gear wheel I2, gear wheel 8, clutch I9, shaft 2, gear wheel 9, gear wheel I3, shaft 6, gear wheel I4, gear wheel '30, gear wheel 3|, gear wheel I0, clutch 25", shaft 3.

If the gear box shown is used as a six-speed gear, the sequence of speeds shown hereunder may be obtained for example (of course, the transmission ratios of the various gear wheels is altered correspondingly):

Forward '14; as I. 11a as II. Illa as IV. No as V.

Va as VI. VIa as VII.

Reverse Ra as B.

As will be seen in Figure 2, mounted on the shaft 22 connected to the clutch-shifting lever 2I for the change-speed dog clutch I1, I8 is an actuating arm 35 which is adapted to be rocked by the piston rod 36 of a piston 38 slidable in a cylinder 31. the right and left of piston 38 respectively, are conduits I40 and I39, of which the former leads Opening into said cylinder 31, on

to'a distributing valve I90 and the latter to a distributing valve 200.

In the same way, secured to the shaft 24 connected to the clutch-shifting lever 23 for the change-speed dog clutch I9, 20 is an actuating 5 arm 45 adapted to be rocked by the piston rod 46 of a piston 48 slidable in a cylinder 41. Opening into this cylinder 41 on opposite sides of the piston 48 are respectively conduits I49 and I 50, which lead to the distributing valves 200 and I90 respectively.

Mounted on the shaft 21 connected to the clutch-shifting lever 26 for the change-speed dog clutch 25 is an actuating arm 55 which is adapted to be rocked by means of the piston rod 56 of a piston 58 slidable in a cylinder 51. Opening into this cylinder on the right and left of the piston 58, respectively, are conduits l59 and I60, the conduit I59 leading to the distributing valve 200 and the conduit I60 to the distributing valve I90.

The end positions of the pistons 38, 48, 58 are denoted by B or V, according to whether the transfer of these pistons into the denoted position is accompanied by an acceleration. or retardation gear change.

To the rear of the distributing valve I90is a shut-off valve I which is moved by the piston I8I acting through the pin I 82 and is held by a spring I83 in the opened position against the surface I84. I85is the seat of the valve in the housing I86. I81 is a conduit for pressure medium which in the present case is connected to the induction pipe of the engine. This con-i duit forks into the two branches I88 and I89 leading to the two housings I86 and I96 of the distributing valves I 90 and 200. I9I is a passage'in the housing I86, and I92 is a communicating conduit. I91 and I98 are control grooves in the distributing valves I90 and 200. MI and 202 are bores in the housings I86 and I96, through which the inner chambers of these housings are connected to the outer air.

I SI and I6I are two shut-off slide valves arranged in the housing 2I0 and connected to the 45 cylinders 31 and 41 by the conduits 201 and 208. 209 is a connecting conduit between the cylinder 51 and the housing 2I0. The pistons I5I and lil have short passages 2H and 2I2 and also annular grooves 205 and 206. 204 is a connect- 50 ing passage between the two guide bores for the pistons I5I and I6I in the housing 2I0;

The piston rods 36, 46, and 56 are provided with grooves 223, 224 and 225. In the extensions of the cylinders 31, 41 and 51 guiding the pistonrods are bores 2I3, 2 and 2I5 which are in communication with the outer air. I

The operation of the control device shown in the drawings will now be'described for changing from the second to the third speed. 60

In Figure 2, the pistons of the gear ratio changing cylinders are shown in the positions corresponding to the second speed. The distributing valves I90 and 200 appropriately coupled together have just been set to the position corresponding to the third speed, so that the conduit I50 of the cylinder 41 is connected by the control groove I91 01' the distributing valve I90 to the passage -I9I which is connected through the conduits I88,

I81 to the induction pipe of the. engine. At the same time, the control groove I98 of the distributing valve 200 connects the conduit I39 of the cylinder 31 to the conduit I89 which is connected to the conduit I81 and hence also to the induction pipe of the engine. The extraction of air 75 through the conduit I89 causes a reduced pressure on the left-hand side of the piston 38 so that the latter moves out position still shown in Figure 2 at first so far to the left until the clutch I1 is in the position of rejection at the counter-clutch on the wheel 8. Engagement does not yet take place since the clutch I1 is rotating'more rapidly than the counter-clutch.

In this position air from the right-handside of the valve I5I is drawn through the conduit 201 and the groove 223 into the cylinder 31 with the result that the small valve I5I moves to the right.

' The bore. 2| I is thereby brought in front of the 1 the induction pipe of the engine.

connection of the conduit I92, while simultaneously the passage 204 opposite is shut off. Air is now drawn into the cond t 201 from the 'conduit I92 with consequent reduction of the pressure on the left of the small piston I8I. The piston I8I is thereby moved to the left by atmospheric pressure and -.the valve I80 is applied to the seat I85 against the pressure of the spring I83. The passage I9I is thereby shut off from Although the I is connected to the passage I9I by the distributing valve I90, no air can be drawn out of it. The piston 48 therefore at first i mains in its right-hand end position and the clutch 20 remainsengaged.

If now, due to the reduction in speed of the engine, the speed of clutch I1 commences to fall below that of ,wheel 8, the clutch I1 is able to engage and hence also atmospheric pressure is able to move the piston 38 completely into its left-hand end position, the right-hand edge of the groove 223 first interrupting the connection conduit 5 between the conduit 201 and the space on the surface I84.

- its higher 'speed.

left in front of the piston 38. When the piston 38 has'moved completely into its left-hand end position, the conduit 201 is connected by the groove 223 to the bore 2I3, through which-the space on the right of the piston valve I5I is now connected to the outer air via the conduit 201 and the groove 223. The piston valve I5I is therefore free to return into its left-hand end position which may be efiected by a return spring (not shown) or by gravity if the valves are suitably disposed. The conduit I92 is thereby connected via the annular groove 205, connecting passage 204 and the annular groove 208 as well as the conduit 209 and the groove 225 in the rod 58 of the piston 58 with the space above the piston 58, .and via the conduit I59, corresponding bore in the valve 200, space above this'valve and the bore 202 in the valve housing with the outer air. Due to the outer air supplied in this way via conduit I92 to the space onthe left in front of the piston I8I equalising the fluid pressures on opposite sides of the piston I8I again returned into itsright-hand end position and the valve I is lifted ofi its seat by the pressure of it's spring I83 and is applied againstthe Ah can now be drawn through the. conduit I88, the passage I! and control groove I91 in the distributing valve I from the conduit I50.

The piston 48 is therefore moved to the'left by atmospheric pressure, the clutch 20 is brought out of engagement and the clutch member I9 is applied to thecounter-clutch member on the wheel 8, where it is at first rejected on account of It comes into engagement as soon as the speed of wheel 8 has been increased to the overtaking thepiston 48 moving into its left-hand end p0- of its right-hand end I the latter is speed by opening the throttle,

sition. The ge'ar changing operation is thus terminated.

In this gear ratio change, the groove 224 on the piston rod 46 does not exert any effect on the valve IGI, since piston 48 and. hence also the conduit 208 in this gear ratio change remain in communication with the outer air through the conduit l49, corresponding bore in'the distributing valve 200, space above said valve and the bore 202 in the valve housing. r

As will be immediately appreciated from Figure' 2, if thedistributing valves I90 and 200 are in positions permitting a retardation gear ratio change by the pistons of one of the two cylinders 31 or 41 and simultaneously an acceleration gear ratio change by the piston of the cylinder 51 the latter gear ratio change is prevented, in the same way as described above, by the valves I5I or I6I by means of the main shut-off valve I80, until the piston of the cylinder 31 or 41 has performed its gear ratio change.

Since, in the construction described, only small shut-off slide valves are required for the individual cylinders, there is obtained a construction which is simpler, cheaper and more reliable and possesses less leakage than is the case with the constructions proposed heretofore. The main shut-on valve (I00) necessary may be more readily made fluid-tight and reliable than the various small shut-off valves previously used for the individual cylinders. The small shut-off valves provided in the present construction and dependentupon the individual cylinders, do not require any great accuracy and fluid-tightness, since they are not permanently under the action of pressure medium.

I claim:

1. A control device for a gear wheel type change speed gear of the kind having disengageable positive engaging members for effecting changes of gear ratio, acceleration of the driving shaft being necessary for the engagement of some of said gear ratio change members and retardation of the driving shaft being necessary for the engagement of others, and in which the selection of at least one of the gear ratios requires the en- 'bers requiring retardation, said control device comprising fiuid pressure operated pistons for engaging and disengaging said gear ratio change members, conduits for pressure medium connected to the cylinders of said pistons, av distributing valve connected to the conduits for carrying pressure medium effective for the engagement of the gear ratio change members requiring acceleration of the driving shaft, a distributing valve connected to the conduits for carrying pressure medi um effective for the engagement of the gear ratiochange members requiring retardation of the driving shaft, a shut-off valve arranged in series with one of said distributing valves, means for maintaining said shut-off valve shut while pressure medium-flowing through the other distributing valve is active for efiectingthe enthe space 'to the right of the,

gagement of gear ratio change members, and

valve shut comprises a fluid pressure operated device acting en said shut-off valve and responsive to fluid pressure transmitted through pressure medium contained in any of said cylinder conduits connected to said other distributing valve.

3. A control device as claimed in claim 1 in which said means for shutting and opening said shut-01f valve comprises a fluid pressure operated device acting on said shut-oil valve in opposition to a spring tending to open said valve, connecting conduits betwee.-- said device and each of said cylinder conduits connected to said other distributing valve, valve means in each 01' saidconnecting conduits for releasing the pressure therein upon the completion of the engagement of the gear ratio change members operated by the pressure in the cylinder conduit with which said connecting conduit is connected, and valve means in said connecting conduits responsive to pressures acting therein to shut-oi! those connecting conduits not under pressure when one connecting conduit is under pressure.

4. A control device for a gear wheel type change speed gear of the kind having disengageable'positive engaging members for eiiecting changes oi gear ratio, accelerationof the driving shaft being necessary for the engagement of some of said gear ratio change members and retardation of the driving shaftbeing necessary for the engagement of others, and in which the selection of at least one of the gear ratios requires the engagement of gear ratio change members requiring acceleration I and of gear ratio change members requiring retardation, said control device comprising fluid pressure operatedpistons for engaging and disengaging said gear ratio change members, conduits for pressure medium connected to the cylinders of said pistons, a distributing valve connected to the conduits for carrying pressure medium e1- i'ective tor the engagement of the gearratio change members requiring acceleration of the driving shaft, a distributing valve connected to the conduits for carrying pressure medium et fective for the engagement of the gear ratio change members requiring retardation of the driving shaft, 9. shut-oil valve arranged in series with said distributing valve connected to the conduits for carrying pressure medium eflective for the engagement of the gear ratio change members requiring accelerationot the driving shaft, means for maintaining said shut-oi! valve shut while pressure medium flowing through the other distributing valve is active for eifecting the engagement of gear ratio change members requiring retardation of the driving shaft, and means for opening said shut-off valve upon the completion of said engagement.

ERWIN DAUSCH. 

